Monday, November 29, 2010

Energía Térmica y Fotovoltaicos

La luz del sol se utiliza para generar la electricidad y energía térmica que consumen los electrodomésticos, la iluminación y los sistemas de calefacción.

El sistema fotovoltaico utiliza células para convertir la luz solar en electricidad. Las células están formadas por una o varias láminas de material semiconductor. Cuando la luz incide en las células, se crea un campo de electricidad entre las capas, logrando el circuito eléctrico. A mayor intensidad de la luz recibida, mayor será el flujo de electricidad generada. El material semiconductor más utilizado en las células fotovoltaicas es el silicio, un elemento que se encuentra fundamentalmente en la arena. El silicio es el segundo material más abundante en la Tierra.

La parte más importante de un sistema fotovoltaico son las células, que son los auténticos generadores de electricidad al recibir la luz del sol. Los módulos reúnen largas series de células en una unidad, y los inversores convierten la electricidad continua en corriente alterna para que se use diariamente.
Las células fotovoltaicas son generalmente de silicio cristalino, cortadas a partir de lingotes o fundidas.
También hay tecnologías capa fina, que depositan el silicio un otro material semiconductor en un soporte de bajo coste.

El rendimiento de una célula solar se mide en términos de eficiencia al transformar la luz solar en electricidad. Mejorar la eficiencia de la célula solar mientras se reduce su coste es un importante objetivo de la industria fotovoltaica.

Plantas de producción eléctrica
Este sistema, también conectado a red, produce grandes cantidades de electricidad fotovoltaica en un punto individual. El tamaño de estas plantas oscila entre varios cientos de kilovatios a decenas de megavatios. Algunas de estas aplicaciones están ubicadas en amplias zonas industriales o rurales.
Sistema domestico de conexión a red
El sistema fotovoltaico conectado a red es la instalación más común para hogares y negocios en zonas desarrolladas. La conexión a la red local de electricidad permite la inyección y venta de la energía generada y su autoconsumo. Se utiliza un inversor para convertir la energía de la instalación solar, de corriente continua, a corriente alterna.

Instalaciones industriales aisladas
La electricidad solar en instalaciones aisladas es frecuentemente utilizada en el campo de las telecomunicaciones, especialmente para conectar áreas rurales remotas a zonas pobladas. Estaciones de repetición para teléfonos

móviles alimentadas con fotovoltaica o sistemas híbridos también tienen un amplio potencial. Otras aplicaciones incluyen señales de tráfico, sistemas de ayuda a la navegación, teléfonos de seguridad, iluminación remota, señales
para la autopista y plantas de tratamiento de agua residual. Hoy, estas instalaciones tienen un coste competitivo, ya que facilitan la conexión de energía en áreas alejadas de los centros eléctricos principales, suprimiendo el alto coste que requiere una conexión de cableado.
Sistemas térmicos:

En cuanto a los sistemas de generación de energía térmica, permiten que tanto a nivel industrial empresas cerveceras, centrales lecheras, industrias alimentaria, papelera, textil y química hoteleras, etc. Que consumen gran cantidad de agua caliente para sus procesos de fabricación o servicios, son de gran utilidad los sistemas altamente eficientes capases de generar gran cantidad de temperaturas constantes, En este caso los equipos que mejor resultados están dando son los de concentración solar, por supuesto estos sistemas se pueden utilizar para el consumo diario en el hogar.

LOS MECANISMOS DE TARIFA REGULADA

Si instala un sistema fotovoltaico en su hogar, toda la electricidad generada puede ser inyectada y vendida al proveedor de electricidad a mayor precio del que paga en su factura mensual. Este mecanismo le permite el retorno de su inversión en poco tiempo. Además si su equipo es capaz de generar los dos sistemas simultáneamente, energía solar térmica y fotovoltaica el beneficio es doble, por el ahorro que supone en carburantes para la calefacción de su hogar y los ingresos obtenidos de la venta de electricidad.
Pero para esto es necesario equipos altamente eficientes, actualmente se está desarrollando un sistema de energía térmica y fotovoltaica por la empresa SolarTron Energy sistem, que han diseñado un sistema de concentración solar llamado SolarBeam, capaz de proveer los dos energías el sistema térmico genera 13kwh de energía térmica y el fotovoltaico de concentración solar es capaz de producir hasta 3.5 kwh de electricidad mediante una superficie de 25×25 cm. Dicho módulo se ofrecerá a un precio asequible y puede utilizarse junto con concentradores SolarBeam ya existentes.

Este equipo posee un mecanismo de seguimiento solar de dos ejes, que permite seguir con precisión la trayectoria del sol. El SolarBeam no necesita de sensores adicionales para ubicar dicha trayectoria, en cambio utiliza un algoritmo celeste único junto con el sistema de posicionamiento global (GPS) a fin de seguir el sol sin importar la estación del año.

Actualmente, el país cuyo mayor éxito en el desarrollo de la energía fotovoltaica es Alemania. España, Italia, Francia y Grecia cuentan también con un amplio desarrollo de este sistema. Los consumidores de electricidad conscientes de la importancia de las energías renovables están cambiando al uso de la energía solar y recibiendo una compensación económica por la utilización de estos sistemas.

Solar Power Uses in Homes and Commercial Buildings

Sunlight is used to generate solar power and solar heat and is consumed by appliances, lighting and heating systems.

The system uses photovoltaic cells to convert sunlight into electricity. The cells are formed by one or more layers of semiconductor material. When the light hits the cells, it creates a field of electricity between the layers, making the circuit. The greater the intensity of light received, the greater the flow of electricity. The most commonly used semiconductor material in photovoltaic cells is silicon, an element that is found mainly in the sand. Silicon is the second most abundant material on Earth.

The most important part of a solar power system are the cells because they are the generators that receive sunlight. The long series of modules molded together in a single cell, convert electricity into alternating current that is used daily.
Photovoltaic cells are usually crystalline silicon, sliced from ingots or castings.
The performance of a solar cell is measured in terms of efficiency to transform sunlight into electricity. Improving solar cell efficiency while reducing costs  is an important objective of the photovoltaic industry.

Electricity Production Plants

This system, connected to the grid, produces large amounts of photovoltaic electricity in a single point. The size of these plants ranges from several hundred kilowatts to tens of megawatts. Some of these applications are located in large industrial or rural areas.
 
Grid Connection for Homes and Businesses
The grid connected photovoltaic system is the most common installation for homes and businesses in developed areas. The connection to the local electricity network allows the injection and sale of solar power generated and reduces the consumption of electricity created by fossil fuel. Photovoltaic systems use an inverter to convert solar energy from, direct current to alternating current.

Solar Power in Industrial Facilities
The stand-alone solar electricity is often used in the field of telecommunications, especially for connecting remote rural areas to populated areas. In addition,  mobile stations fed  by photovoltaic or hybrid systems also have a huge potential. Other applications include traffic signal systems, navigational aids, security phones, remote lighting, signs for highway and water treatment plants.

Solar Hot Water Systems:
As for the systems thermal power generation is attractive to industrial breweries, dairies and food industries, paper, textile and chemical hotels, etc. These industries consume large amounts of hot water for their manufacturing processes or services and need solar hot water system that can generate large amounts of hot water. In this case the systems that give the best results are concentrating solar power, like the SolarBeam Concentrator.

Feed In Tariffs for Solar Power

If you install a photovoltaic system in your home, all the electricity generated can be connected to the grid and sold to the electricity supplier at a higher price than it pays out on your monthly bill. This mechanism allows the return of your investment in no time. Also, if you have a SolarBeam Concentrator, that is capable of generating thermal and photovoltaic energy, the benefit is twofold. There is savings on fuel for heating your home and also from selling the solar power to the grid.

However, not all systems on the market have this dual purpose. Solartron Energy systems, which have designed a solar concentrator system called SolarBeam,is  capable of providing the solar power and solar hot water. 1 SolarBeam provides 13kwh of thermal energy and up to 3.6kWh of electricity. The photovoltaic module is an upgrade and can be added onto existing solar thermal systems. This way, the upfront cost is reduced, but you still have the option of creating electricity in the future.

Currently, the countries who are having success in the development of PV is Germany. Spain, Italy, France and Greece also have a wide development of this system. Electricity consumers aware of the importance of renewable energy are changing the use of solar energy and receiving financial compensation for the use of these systems.

DIFFERENCE BETWEEN SOLAR CONCENTRATOR AND FLAT PANELS

The problem in flat solar panels is that they have a static position, more than 45 ° this means that they only take advantage of a few hours on sunlight and in most cases they do not have a tracking system. Another problem is that there are heat losses in the flat panel, since they depend on the temperature difference between the absorber and the air outside, due to the sun and the construction of the collector. In the case of flat panels, you need to increase the amount of flat panels when you want hotter water temperatures because the efficiency drops from 75% to 35% when you want water at 95 Celsius. If you check out the SRCC data for flat panel performance you will see how the efficiency drops based on outside temperature and the temperature of the water being heated.

Flat panels perform best at low temperatures, like 50 Celsius and in areas where a user only wants to heat a hot water tank, or where there are space issues. However, for clients who want to see major energy savings, then they need to use a solar concentrator like a SolarBeam from SolarTron Energy Systems since it can produce up to 13kW of thermal heat per hour from an area of 175 sq. feet. It is a perfect solution for companies that have more than 900 liters of water that needs to be heated by a solar hot water system . 1 SolarBeam can heat 900 liters from 12 degrees Celsius to 60 degrees Celsius in 4 hours.

SOLAR CONCENTRATOR, THE BEST SOLAR HOT WATER SYSTEM.

The main feature of a solar concentrator is that it has a tracking system that allows the solar rays to reach the collector throughout the day. This is indispensable for harnessing solar energy throughout the day.

Another advantage is that solar concentrators are not affected by the stagnation of heat, since it has a tracking system the solar hot water system can move out of the sun once the temperature of the water has reached the desired temperature.

The gear train on the solar concentrator is 2 axis. One axis moves the system from  East to West. The other axis moves the system North-South track, which will improve the capture of radiation received by optimizing over the year. Because in winter, the rays fall more obliquely, and in summer more horizontal. In addition, this system can work in northern and southern hemispheres and at the equator because of its intelligent tracking system.

MOVEMENT CONTROL
To perform motion control, you need the help of a mathematical algorithm and we know exactly the position of the sun for any time of year with absolute precision

DESCRIPTION
The solar concentrator is the most efficient solar hot water system. This technology has highly reflective parabolic mirrors, specially designed to collect and use solar power by concentrating sunlight into a single point or focus, (similar to the principle of a magnifying glass).
The  solar hot water system provides up to 13 kWh of heat (44,350 BTU / hour), compared with other conventional technologies, the amortization period of your initial investment will be much shorter, at least 6 years.

Multiple Application
Solar concentrators can be used in conjunction with an absorption chiller for applications that require air conditioning. Unlike traditional heat transfer systems using vacuum line or photovoltaic panels, the multifunctional nature of the solar concentrator provides both hot water, air conditioning and heating.
Hence, also useful for the supply of electricity, which will be available by summer 2011.

The solar thermal technology can be used for the following applications:
• Heating at home or industrial buildings
• Air Conditioning, together with an absorption chiller
• Water Heating (up to 95 Celsius)
• Process heat